Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!killer!vector!nobody From: westmark!dave@rutgers.edu (Dave Levenson) Newsgroups: comp.dcom.telecom Subject: Re: Tip and Ring reversal Message-ID: Date: 25 Dec 88 22:31:48 GMT Sender: chip@vector.UUCP Lines: 23 Approved: telecom-request@vector.uucp X-Submissions-To: telecom@bu-cs.bu.edu X-Administrivia-To: telecom-request@vector.uucp X-TELECOM-Digest: volume 8, issue 209, message 8 In article , john@jetson.UPMA.MD.US writes: > ...wiring scheme which would result in tip and ring > being reversed for some number of outlets within a house... > ... What kind of problems will this polarity reversal cause?... Older 2500 sets (single-line touch-tone) will not generate touch tones when tip and ring are reversed. Some 2500 and 500 (dial-pulse) sets will not ring when the loop is reversed. The newer sets are largely insensitive to polarity. It has been my experience (from several years of selling and installing business telephone systems) that about half of the loops in the country are reversed an odd number of times between the central office and the subscriber's equipment. When installing ground-start or DID equipment (where loop polarity is important) we usually had to swap leads on about half of the trunks serving a typical PBX installation to make things work right. For recent-manufacture single-line sets, however, it will probably make no difference. -- Dave Levenson Westmark, Inc. The Man in the Mooney Warren, NJ USA {rutgers | att}!westmark!dave